Hoisting apparatus



Oct. 22, H, ENARD 1,732,507

HOI STING APPARATUS Filed Sept. 25, 1925 {Sheets-Sheet 1 F rm uylullmulmlmwnmmml l is. INVENTOR r M yz azgd Oct. 22, 1929. H. ENARDHOISTING APPARATUS Filed Sept. 25, 1925 T Sheets-Sheet Oct. 22, 1929.

H. ENARD HOISTING APPARATUS Filed Sept. 25, 1923 7 Sheets-Sheet INVENTOROct. 22, 1929. ENARD 1,732,507

HOISTING APPARATUS Filed Sept. 25, 1.925 7 Sheets-Sheet 4 3 4 74 76 75INVENTOR 3 W 50W? 0st. 22, 1929. ENARE; 1,732,507

HOISTING APPARATUS Filed Sept 25, 1923 7 Sheets-Sheet 5 INVENTOR Oct.22, 1929. H. ENARD HOISTING APPARATUS Filed Sept. 25, 1925 7Sheets-$heet 6 Z MIM Oct. 22, 1929. H. ENARD HOISTING APPARATUS FiledSept. 25, 1923 7 Sheets$heet 7 Patented a. 22, 1929 T 0w ee vAm'A An airoperated; brake hand; eIigaghig a suitable surface eh one at the held d'ihiie, projficies mezih 01 holding the thicket sitspended afterhbistifiti the also, if de red, 130 assisting 1 bfieke'taftelfjlowefing. The efhttql0t peed hen low ring is sme lyeceeliipiiehee tv dynamic braking on the heistmotoi whefe direetcurrentis used a'ii d Shiitetines it .agdel- T the bucket. Even withti'iliexjaerithtfite (it a relativelylarge amount 01" p'div eratihgthe i61*, the 01 u requires 1 several seeii dsf n' r e time with It enginethan is needed whenftheeidsih czizibe alieived to epitiifrf eely releaclutch eonhe it te't et l an'ieljht df eleetl' 'e pm b y the 4115i Whilethe h ieltetieojj'e J lilo tradtioii (if the total power cen'euihed'iifan entireeycle of eperatiqi s, and hence afl 'ts the cost of ioii' ei'fdt' hahtili ig the lflatti'ia'l.

i/Viththe type of clutch geriefalljf need iii con s tluetiehs Qfj/[i sChara t j1., it has njijt heretetoze beeriffp mttpfaet cable t 11115 asecol'iti' aii' operated clutch on the dluiii shaft, to permittheclosing drum to sjiiii freely W e i chlmt Hgt 1e bucke'tgaoiiaeeetuit of the difiieiil tylin getting the eilqj fily Oi ,air

collars on the shaft has prevented the use of that method of operating aclutch for the closing drum on the larger constructions, particularlywhere the three drums on a single shaft are used. As it is desirable tokeep the load suspended from the trolley approximately balancedsideways, the closingdrum can not be placed at one end of the drum shaftand the hold drnm at the other end, except-by reeving' the ropes throughthe bucket and anchoring them on the trolley so that the bucket hangs ina bight of the lines, which requires the ropes to run through the bucketwhile it is being hoisted and lowered, resulting in a loss of power dueto the friction on all the sheaves over which the closing rope passes inthe bucket.

By the present invention there is provided a construction which embodiesall of the above mentioned advantages incident to hav- 1 ing the closingand the two hold drums mounted ,uponthe same shaft, with the hold drumson the ends of the shaft, but in which the objectionable feature ofhaving the closing. drum permanently geared to the hoist motor isavoided by the provision of a second clutch to connect the closing drumto the motor, permitting free spinning of the drum for opening thebucket, both clutches being operated by means which does not involve theprovision of an air cylinder in any of the drums, thereby obviating thenecessity for rotating air: connections to take the air into the drumshaft,n0-r are any sliding collars or similar connections required onthe drum shaft.

In the accompanying drawings, there is shown, for purposes ofillustration only, one embodiment of the present invention, it beingunderstood that the drawings do not define the limits of the invention,as changes may be made in the construction and operation thereindisclosed without departing from the splrlt of the invention or thescope of mybroaderelaims.

In the drawings:

Figure 1 is a plan view of the trolley, of a hoisting and conveyingbridge structure embodying my invention.

Figure 2 is a side elevation of the trolley and grab bucket suspendedtherefrom.

Figure 3 is an end view of the main hoisting gear, showing one of theclutches associated therewith and the means for operating the same.

Figure 4 is a sectional view on the line IV-IV of Figure 3. I V

Figure 5 is a view, partly in elevation and partly in section, of thedouble acting clutch operating cylinder and parts associated therewith.

Figure 6 is'a sectional view taken approx imately on the line VI-VI ofFigure 5.

Figure 7 is a vertical sectional view taken i on the line VII VII ofFigure 5.

mounted upon axles 7 driven by trolley traversing motors 8.

Mounted upon a shaft 9 journaled in the frame3 are the two hold drums 10and 11 and the closing drum 12, the hold drums being keyed to the shaftand the closing drum being mounted loosely thereon. Also mounted torotate freely upon the shaft 9 is a main hoist gear 13, said gear beingarranged intermediate the adjacent ends of the hold drum 10 and closingdrum 12.

A ring gear 1 1 (Figure 4) is rotatably sup ported at one side of themain gear 13 upon rollers 15 mounted upon pins 16 carried by said maingear.

The main gear and ring gear are driven at the same speed by a hoistmotor 17. This motor has a pinion 18 mounted upon its armature shaftwhich meshes with a gear 19 on the end of an intermediate shaft 20journaled in suitable hearings in the trolley carriage. The intermediateshaft carries a pinion 21 meshing with the main gear 13 and also carriesa pinion 22 of the same pitch diameter as the pinion 21. By reference toFigure 7, it will be seen that the pinion 22 meshes with a pinion 23mounted upon a short shaft 24, the pinion 23 meshing with a pinion 25journaled upon a shaft 26 beneath and parallel to the shaft 20. Anotherpinion 27 of the same diameter as the pinion 25 is also rotatablymounted upon the shaft 26- and is integrally connected with the pinion25 by means of a sleeve 28. The pinion 27 meshes with the ring gear 14.While I have shown the pinions 21 and 22 as being mounted upon anintermediate shaft 20, it will be apparent that these pinions might bemounted directly upon the armature shaft, if desired, and the pinion 18and gear 19 eliminated.

Referring to Figures 5 and 6, the pinion 23 is adapted to be moved ashort distance in opposite directions from its central position, inwhich its axis is in the same vertical plane as the axes of the pinions22 and 25. For this purpose the pinion 23 is operatively connected to adouble acting fluid pressure cylinder 29, the piston 30 whereof has itspiston rod pivotally connected. to cite end of: pair of bars arranged atopposite sides at the pinion arid having the short shaft 24 ex tendingtherethrouglu These bars extend through guide 33". Each end of the shaft24 extends through an e-ye34 formed on theend of a. stem Each stem 36extends through two spaced plates 37 and 38, which are slidably mountedupon a pair of parallel rods 39 projecting from an end wall ofthecylinder' Each stem 36 is surrounded by a coil spring atlwhichabutsat its ends against the plates 37 and 38. and normally maintainsthese platesiin engagement with nuts 41 and on the rods 39. Thesesprings normally maintain the pinion 23 in its central po'si-- tion, inwhich position of the pinion both" ends of the cylinder 29'are open tothe exhaust.

The opposite ends oi. the cylinder 29 connected by pipes and 4A withvalve casings 45 and 461 These valvecasings are connectedby otherpipesd'i and 48 60 a pipe 49 leading to a suitable source of pressurefluid supply, preferably compressed air. The 2; valves in these valvecasings may be operated by any" suitable-means and I show, for pun" poseof illustration only,- solenoids 50 and 51 for that purpose.

The solenoid 50 is shown in detail in Figgmure 9; it being understoodthat the solenoid 51 is of identical construction. It comprises a coil:52Jsurroun'ding stationary liollowcore 53: A plunger 54le'is mountedi'nsaid core and carries an ann'rature 55 upon its upper end; 3'5 l helower end of the plunger constitutes a valve 56 adapted to ehgage avalve seat' in theupper endtof a sleeve57. The valve 56 is connected bya:val've stenn58With another valve 59'adapted' to engage a val've seatin the lower end of the sleeve 57. The valve casing lli has a chamber 60therein beneath the sleeiie 57" and communicating with thischain her. isthe supply pipe 4'1 leadingfronr the source-of fluid supply; The pipe 43leading 5. to one end of the cylinder 29 is tapped! into the valvecasing and cominunlcates' wltlrt-he interior of the sleeve 57.

The valve casing i has another chamber Glitherein above thesleeve 57and. this chamberv communicates away from itsseat'. Under theseconditions the end of the cylinder which is connected.

-1. by thepipe 43 with the'val've casing; is open to the exhaust. .When, hoivevertthe coil 52 isenergized, the-armature b is att actedtowardsthe core 53;.thereby moving thevalve- 56 into engagement withitsseat and the valve C of the cylinder from the exhaust andplaces it"in communication with the source of fluid supply through i the pipe 43-,sleeve 57, ohanr her" and pipe 1-472 The o'perationeofxthe" parts shownin Fig.-

mess and 6 is asl follows: Normally; as already stated, both: ends ofthe cylinder 29' are open to the exhaust and the springs 40=1nain= tain.the pinion 23in its central position. Let it be assumed that thesolenoid 50 is energized. This places the right-hand end of the cylinder29 as viewed in Figures 5 and 6 in communication with the source offluid supply, the lefthand end ot the cylinder remaining open to theexhaust. The piston 30 is thereforemoved to the left, thereby moving theshaft 24: in the same direction. The pinions 25 and 27 will, therefore;be rotated ni counter-clockwise direction through an angle couespondingto twice the amount of motion of the shaft 2 1', since the tooth contact between the pinions 22 and 23 serves as the fulcrum of a lever ofthethird class. The ring gear 14; Will theretorabe rotated in aclockwise direction, as viewed in Figure 3 relative to the main gear 13.It will be apparent that the distance moved by the teeth oi the ringgear will be equal to twice the distance moved by the shaft 24. Itwillalso be apparent that this relative movement between the ring gear 1%and main gear 18 willtalreplace-irrespective of whether the pinion beingdriven by the hoist motor 17 or is stationary. If instead of thesolenoid 50 being energized the solenoid 51 is energized, their the"piston 30 will be moved to the right and consequently the pinions 25and27 will be; rotated inl a' clockwise direction and the ring gear 14 willbe rotated in in counter clocmvise direction" relative to' the main x 1gear 13;-

. The springs 40 will be put under compres sion upon movement ofthe'piston 30in either direction; hen thepiston nioves tothe left theeyes-84 on the stems iitiengage the plates 37 and move them to the left,thereby conr pressing. springs 40, and when the piston moves to'tlieright the nutson the ends of the stems-36 engage the platesBS and movethem to the right, thereby compressing the said y springs.

Referring toFigure l, the drains l0 and 12 have flanges (53and '64a011their adjacent ends positioned within the rim of the main gear. Theperipheral surfaces of theseilangescom stitute clutch engaging surfaces;The main gear has associated therewith a clutch for cooperation with theclutch surlace of' the flange 63" of the hold drnn'r 10 and anotherclutch of identical construction for cooper-- my ation with the clutchengaging surface otthe flange 64 of the closing drum 12. Thereforeitwillonly benecessa'ry for the purpose of understanding the presentinvention to dc scribe one of these clutches;

The clutch for cooperation with the flange- 63' of the hold dru1'n 10 isshown i'n Figure 3w This clutch comprises a: clutch band 65which-isnanchored at one end upon a pin 66 carried by themain gear. Theother end? of 1.30

this band is pivotally connected to a lever 67 pivotallymounted uponsaid pin. A con-. necting rod 68'is pivotally connected at one end tothe lever 67 and at its other end is ,pivotally connected to a lever 69pivoted upon a' pin 70 carri d by the main gear. A

stem 71 is pivotally connected at one end to said lever 69 and extendsthrough an opening in a spoke of the main gear. Said stem has a nutmounted upon its. other end and surrounding thesame, between said nutand said spoke isa coil spring 72. The spring 7 2 normally maintains theclutch band in holding engagement with the surface of the flange 63. Itwill be understood that in like manner a clutch of identicalconstruction is associated with flange 6a and is normally held inholding engagement withsaid flange.

Relative movement of the ring gear 14 with respect to the main gear 13,as effected by the means disclosed in Figures 5 and 6. serves to releaseone or the other of the clutches as desired. For this purpose the ring.gear is operatively connected to the connecting rods 68 and 68 of therespective clutches. This operative connection comprises a T-shapedJlever? 3 (Figure 8) pivoted upon a pin 7 4 secured in the main gear 13and projecting within the interior of the rim thereof. The lever73 ishollow to receive a pin 7 5 which is pivoted at one end to the ring gear14 upon a pin 76 carried by said ring gear. It will be seenthat'relative move.- ment of the ring gear 14 in one direction or theother with respect to the main gear 13 will rock the lever 73 about itspivot 74. The lever 73 is connected by links 77 with a lever 78 pivotedupon a pin 79 carried by the main gear. By reference to Figure 11 itwill be seen that the opposite ends of the lever 78 extend intohorizontal slots in the connecting rods 68 and 68 and carry pins 80 and81 gear in order to open the bucket, for example,

the solenoid 51 will be energized, thereby causing the piston 30 to bemoved to the right and'the pinion 27 to berotated in a clockwisedirection. Conseqeuntly the ring gear will be rotated in ananti-clockwise direction relative to the main gear, thereby rocking thelever 78 aboutits pivot 79. This will cause the pin to engage the endwall of the slot 82 and move the connecting rod 68' to the left torelease the clutch engaging the flange 64. Rocking of the lever 78 forthis purpose will have no efl'ect whatever upon connecting rod 68 of theclutch engaging flange 63 of hold drum 10, for the reason that'the pin81 will simply travel in the slot 83 but will not travel far enough toengage the opposite end wall of the slot 83 and move connecting rod 68to the right. On the other hand, if it is desired to release the clutchengaging the flange 63 of hold drum 10 in order. to close the bucket,for example, the solenoid 50, will be energized, thereby elfectingmovement of the piston 30 to the left. This will result in the pinion 27being rotated in a counter-cloclnvise direction and the ring gear 14 ina clockwise direction with respect to the main gear. The lever 78 willtherefore be rocked about its pivot 79 in a direction to cause the pin81 to engage the end wall of the slot 83 and. mov the connecting rod 68of the clutch associated with the flange 63 to the left, therebyreleasing the hold drum 10 from the main gear.

The other hold drum 11, as is customary, has a brake associatedtherewith. In Figure 10 I have shown a brake of the character ordinarilyemployed, which comprises a brake band 81 engaging a rim 85 on the drum9.- One end of the band is anchored upon a pin 86 and the other end isconnected to one end of a bell crank lever 87 by means of a connectingrod 88, the lever 87 being pivoted intermediate its ends upon said pin86. The other end of lever 87 has the end of a piston rod 89 pivotedthereto, said piston rod being connected to a piston 90 working in afluid pressure cylinder 91. A spring 92 surrounding the piston rodbetween an adjustable abutment 93 and the piston 90 normally maintainsthe brake band in holding engagement with the rim. In order to releasethe brake band pressure fluid may be admitted into the cylinder abovethe piston through a pipe 94 which is connected to a valve casing 95.This valve casing is connected by a pipe 96 to the source of pressurefluid supply and has an exhaust pipe 97. The valve construction withinthe casing may be identical with that within the casings 15 and 46 andmay be operated by a solenoid 98 of identical construction with thesolenoids 50 and 51.

A brake 99 may be associated with the armature shaft of the motor 17 inorder to prevent a suddenly applied reverse load on the gears andbearings that results from a sudden application of the brake associatedwith the hold drum 11. This brake may be of the usual shoe or post typewhich is equally effective in both directions of rotation of thearmature shaft and prevents over-travel when the power is shut off thehoist motor.

The advantages of the present invention arising from the provision of asecond clutch for connecting the main gear to the closing drum andoperated in the manner disclosed should be apparent to those skilled inthe art. As already pointed out, the provision of the second clutch doesnot require an air cylinder in the closing drum. Furthermore, the aircylind r heretofore employed in one of the hold drums is eliminated.Consequently no rotating air connections are needed to take the air intothe drum shaft. The bucket is dumped in several seconds less time thanis possible when the hoist motor must rotate during the dumping andthere is a considerable saving in power consumption and in the wear andtear on the hoist motor and associated parts.

The aboveare important advantages arising from the invention but thereare still others. By the provision of means for operating both clutchescomprising a pinion shiftable in one direction to release one of theclutches and shiftable in the opposite direction to release the other ofsaid clutches, it is impossible for the opera-tor to inadvertentlyrelease both clutches at the same time. A double acting fluid pressurecylinder of the type shown mounted upon the trolley frame floor is adesirable means for controlling the movements of the shiftable pinion,as the cylinder, being stationary, is accessible for inspection whilethe hoist is being operated, and repairs arev more easily made thanwhere the cylinder is inside of a drum. However, other means may beemployed with equally good results for actuating the shiftable pinion,for eXample two solenoids or two single acting cylinders might be usedor a hand lever might be employed for changing the position of thepinion while still retaining the advantage of being unable to hold bothclutches released at the same time.

i A further advantage arising from the pro vision of means of thecharacter shown for controlling both clutches is due to the fact thatthe release of one clutch cannot take place while the other clutchremains released, as, for example, because of any binding or othermechanical trouble preventing the other clutch from going to theclutch-applied position. This fact will be apparent from a considertionof Figure 12. Let it be assumed that the connecting rod 68' has beenshifted to the left to release the clutch of the closing drum and thatupon return of lever 78 to normal position, as shown in dotted lines,said connecting rod 68, remains in the position shown by reason ofbinding or other mechanical trouble. In that case the pin 80 ispositioned at the right-hand end of slot 82, as shown in dotted lines.If thereafter the ring gear 14 is moved in a direction to shifttheconnecting rod 68 to the left to release the clutch of the hold drum1(), the pin 80 will engagethe right-hand end wall of the slot 82 andpositively move the connecting rod 68 to the right to thereby apply theclutch to the closing drum. In case the binding action is such as toprevent movement of the connecting rod 68 to the right, then the ringgear 14 will simply be held against relative movement with respect tothe main gear 13 and the hold drum clutch will not be reease l. The samething will take place in case the hold drum is heldin the releasedposition and it is attempted to release the closing drum clutch.

I claim 1. Hoisting apparatus, comprising a drum shaft, a pair of drumson said shaft, a driving means on said shaft, clutches for operativelyconnecting said driving means to said drums, a common clutchactnatingmechanism for both drums rotatable about the axis of the shaft andconnected for rotation with the driving means, and means for effectingrelative rotation of the clutch actuating mechanism and the drivingmeans for controlling said clutches, substantially as described.

2. Hoisting apparatus, comprising a drum shaft, a pair of drums on saidshaft, a driving means on said shaft, clutches for operativelyconnecting said driving means to said drums, a common clutch actuatingmechanism for both drums rotatable aboutthe axis ofthe shaft andconnected for rotation with the driving means, means for effecting operative rotation of the actuating mechanism in one direction fordisconnecting one drum from the driving means, and means for effectingoperative rotation of said actuating mechanism in the other directionfor disconnecting the other drum from the driving means, substanatiallyas described.

Hoisting apparatus, comprising a drum shaft, a pair of drums on saidshaft, a driving means on said shaft, clutches for operativelyconnecting said driving means to said drums, a common clutch actuatingmechanism for both drums rotatable about the axis of the shaft andconnected for rotation with the driving means, means for effectingoperative rotation of the actuatingmechanism in one direction fordisconnecting one drum from the driving means, and means for effect ingoperative rotation of said actuating mechanism in the other directionfor disconnecting the other drum from the driving means, the clutchesand clutch actuating mechanism being arranged to disconnect either ofthe drums from the driving means or to simultaneously connect both drumsto the driving means, substantially as described.

a. Hoisting apparatus, comprising a drum shaft, a pair of drums on saidshaft, a driving means on said shaft, clutches for operativelyconnecting said driving means to either of said drums, clutch actuatingmechanism, a portion of which is common to both drums and is rotatableabout the axis of the shaft, gearing for rotating the clutch actuatingmechanism in synchronism with the driving means and means for shiftingsaid geartially as described.

ing about the axis of the driving means and independent thereof forcontrolling said clutches, substantially as described.

5. Hoisting apparatus, comprising a drum shaft, a pair of drums on saidshaft, a driving means on said shaft, clutching means for operativelyconnecting the driving means to either of said drums, .a common meansfor rotatingthe clutch actuating mechanism in synchronism With thedriving shaft, and fluid actuated means for shifting said gearing toefiect a relative rotation of the clutch actuating mechanism and thedriving means for controlling said clutches, substantially as described.g

7. Hoisting apparatus, comprising a drum shaft, a pair of drums on saidshaft, a driving means on said shaft, clutches for operativelyconnecting said driving means to either of saiddrums, clutch actuatingmechanism rotatable about the axis of the shaft, gearing for rotatingthe clutch actuating mechanism in synchronism with the driving shaft,and double acting fluid pressure means for shifting said gearing toeffect a relative rotation of the clutch actuating mechanism in twodirections with relation to the driving means for controlling saidclutches, substanfor controlling said clutches, the clutches and gearingbeing arranged to disconnect either of the drums from the driving meansor to simultaneously connect both drums to the drivingmeans,substantially as described.

9. Hoisting mechanism having a drum, driving-means for the drum, clutchelements connected to the driving means and the drum, one of saidelements comprising an expansible and contractible member, actuatingmeans rotatable relative to the driving means and about; the axis of thedrum for expanding and contracting said member, a second driving meansfor rotating the actuating means in synchronism with the first mentioned driving means, and means for supplementally actuating said seconddriving means relative to the first mentioned driving means forexpanding and contracting said member, substantially as described.

10. Hoisting mechanism comprising a plurality of drums, driving meansfor the drums, clutches for connecting the drums to the driving means,each clutch member comprising an expansible band carried by the drivingmeans, actuating means rotatable relative to the driving means forexpanding and contracting the band, a second driving means for rotatingthe actuating means in synchronism with the first mentioned drivingmeans, and means for shifting said second driving means in twodirections relative to the first mentioned driving means for contractingand expanding the band, substantially as described.

11. Hoisting mechanism having a drum, driving means for the drum, clutchelements connected to the driving means and the drum, one of saidelements comprising an expansible and contractible member, actuatingmeans rotatable relative to the driving means and about the axis of thedrum for expanding and contracting said member, a second driving meansfor rotating the actuating means in synchronism with the driving means,and fluid pressure means for supplementally actuating said seconddriving means relative to the first mentioned driving means forexpanding and contracting said member, substantially as described.

12. Hoisting mechanism comprising a plurality of drums, driving meansfor the drums, clutches for connecting the drums to the driving means,each clutch member comprising an expansible band carried by the drivingmeans, actuating means rotatable about the driving means for expandingand contracting the band, second driving means for rotating theactuating means in synchronism with the first mentioned driving means,and fluid pressure means for supplementally actuating said seconddriving means in two directions relative to the first mentioned drivingmeans for contracting and expanding the band, substantially asdescribed.

18. Hoisting apparatus, comprising adrum shaft, a pair of drums on saidshaft, a main gear on said shaft, means for driving said gear, a clutchfor operatively connecting said gear to one of said drums, a clutch foroperatively connecting said gear to the other of said drums, and meanscommon to both clutches for normally operating them independently, saidmeans comprising a train of gears one of which is rotatably mounted onsaid main gear andoperatively connected to saidclutches and another ofwhich is bodily shiftable in one direction to effect operation of one ofsaid clutches and bodily shiftable in the opposite direction to eifectoperation of the other of said clutches through said ro tatable gear,substantially as described.

14. Hoisting apparatus, comprisingadrum shaft, a pair of drums on saidshaft, a main gear on said shaft, means for driving said gear, a clutchfor operatively connecting said gear to one of said drums, a clutch foroperatively connecting said gear to the other of said drums, and meanscommon to both clutches for normally operating them llldQ. pendently,said means comprising a train of gears one of which is rotatably mountedon said main gear and operatively connected to said clutches and anotherof which is bodily shiftable in one direction to effect operation of oneof said clutches and bodily shiftable in the opposite direction toeffect operation of the other of said clutches through said rotatablegear, the arrangement being such that either or both clutches can bemaintained in clutching engagement with their drums.

15. Hoisting mechanism having a drum, driving means for the drum, clutchelements connected to the driving means and the drum, one of saidelements comprising an expansible and contractible member, actuatingmeans rotatable about the axis of the driving means for expanding andcontracting said member, driving mechanism for rotating the actuatingmeans in synchronism With the driving means, said driving mechanismincluding a gear having a shiftable spindle, and means for shifting saidspindle for shifting said driving mechanism about the axis of thedriving means and relative to the driving means for expanding andcontracting said member, substantially as described.

16. Hoisting apparatus, comprising a pair of drums, a main gear, meansfor driving said gear, a clutch normally operatively connecting saidgear to one of said drums a clutch normally operatively connecting saidgear to the other of said drums, each of said clutches comprising aspring-applied band engageable With a surface of the corresponding drum,and means for actuating said clutches inclependently to releasedposition, said means being effective to positively return one clutch toclutch-applied position simultaneously with the actuation of the otherclutch to released position, substantially as described.

17. Hoisting apparatus, comprising a drum shaft, a pair of drums on saidshaft, a main gear on said. shaft, a clutch for operatively connectingsaid gear to one of said drums, a clutch for operatively connecting saidgear to the other of said drums, a ring gear rotatably mounted upon saidmain gear and operatively connected to both of said clutches, and meansincluding a gear train for normally driving said main and ring gears atthe same angular speed, one gear of said train being bodily movable inone direction to effect a rela ti xqe rotation in one direction betweensaid main and ring gears to operate one of said clutches and bodilymovable in the opposite direction to effect a relative movement betweensaid main and ring gears in the opposite direction to maerate the otherof said clntches, substantially as described.

18. Hoisting apparatus, comprising a pair of drums, driving gueans,spring-applied ban dcl ch for connecting said driving means with o M ofsaiddrums, a spring-applied band clutch for connecting said driving"means with the other of said drums, and controlling means for saidclutches including mca s for pos tfiuely returning either of them fromre le .d to applied position simultaneously the movement of the otherthereof to relea; d position, substantially as described.

LS}, Hoisting apparatus, comprising a pair of drums, driving means, aspring-applied clutch for connecting said driving means with one of saiddrums, a spring aprand ch for connectin laid drivtn the other of saiddrums, and

pl; ,1 t e mea vi means common to said clutches for moving either ofthem to released position independently of the other and including meansfor p -.i.tive ly returning either of said clutches from released toapplied position simultaneously With the movement of the other toreeased position, substantially as described.

20. Hoisting apparatus, comprising a pair of drums, driving means, afriction clutch for connecting said d 'iving means with one of saiddrums, a friction clutch for connecting said driving means with theother of said drums, each of said clutches including spring means fornormally maintaining it applied, and means common to said clutches formoving either of them to released position independently of the otherand including means for positively returning either of said clutchesfrom released to applied position simultaneously with the movement ofthe other to released position, substantially as described.

21. Hoisting apparatus, comprising a pair of drums, driving means, aspring-applied band clutch for operatively connecting said driving meanswith one of said drums, a spring-applied band clutch for operativelyconnecting said driving means With the other of said drums, and meansfor releasing said clutches independently, said means being in capableof releasing both of said clutches at the same time, substantially asdescribed.

22. Hoisting mechanism having a plurality of drums, driving means forthe drums, a clutching element connected to each drum, a clutch band foreach clutching element connected to the driving means, actuating meansrotatable about the axis of the driving means for contracting andexpanding the clutch bands, gearing for rotating the actuating means insynchronism with the driving means, said gearing including a gear havinga shiftable spindle, and means for shifting said spindle a predetermineddistance in opposite directions for shifting said driving mechanismabout the axis of the driving means and relative to the driving meansfor expanding and contracting either of said bands, substantially asdescribed.

' 23. Hoisting apparatus, comprising a pair of drums, driving means, aspring-applied band clutch for 'operatively connecting said drivingmeans with one of said drums, a spring-applied band clutch foroperatively connecting said driving means with the other of said drums,and means for releasing said clutches independently, said meansoperating to positively insure either of said clutches being maintainedin applied position when the other is inreleased position, substantiallyas described.

24. Hoisting apparatus, comprising a drum, driving means therefor,clutch means rotatable with the driving means and effective forcontrolling the operative connection of the driving means with the drumupon non-synchronous rotation of the driving means and the clutch means,a second driving means for rotating the clutch means in synchronism withthe first mentioned driving means, and means for effectingnonsynchronous rotation of the driving means.

25. Hoisting apparatus comprising a drum shaft, a pair of drums on saidshaft, a driving means on said shaft, clutches for operativelyconnecting said driving means to either of said drums, a commonactuating means for actuating the clutch of either drum and rotatablewith a drum after its clutch has been actuated, and means for rotatingsaid actuating mechanism relative to the drums so as to control saidclutches, substantially as described.

In testimony whereof I have hereunto set in hand.

y HANS ENARD.

